[swift-evolution] Removing enumerated?

Charlie Monroe charlie at charliemonroe.net
Tue Jan 31 08:54:11 CST 2017

> On Jan 31, 2017, at 3:24 PM, Chris Eidhof via swift-evolution <swift-evolution at swift.org> wrote:
> Hey everyone,
> I've organized a number of Swift workshops over the last two years. There are a couple of things that keep coming up, and a couple of mistakes that I see people making over and over again. One of them is that in almost every workshop, there's someone who thinks that `enumerated()` returns a list of (index, element) pairs. This is only true for arrays. It breaks when using array slices, or any other kind of collection. In our workshops, I sometimes see people doing something like `x.reversed().enumerated()`, where `x` is an array, and somehow it produces behavior they don't understand.

What is the behavior that you'd like?

for x in [1, 2, 3].reversed().enumerated() {

produces (first column is the index, second the element):

(0, 3)
(1, 2)
(2, 1)

- it IMHO behaves as one would expect - it returns an index into the sequence that you are enumerating...

> A few ways I think this could be improved:
> - Move enumerated to Array
> - Change enumerated to return `(Index, Iterator.Element)` (this would mean we at least need to move it to collection)
> - Remove enumerated
> - Keep things as is
> In any case, just wanted to share my experience (gained from teaching people). 
> -- 
> Chris Eidhof
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> swift-evolution at swift.org
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